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<title>WebGL EXT_clip_control Conformance Tests</title>
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"use strict";
description("This test verifies the functionality of the EXT_clip_control extension, if it is available.");

debug("");

var wtu = WebGLTestUtils;
var gl = wtu.create3DContext("c");
var ext;
const w = gl.drawingBufferWidth;
const h = gl.drawingBufferHeight;

function runTestNoExtension() {
    debug("");
    debug("Check the parameters without the extension");
    shouldBeNull("gl.getParameter(0x935C /* CLIP_ORIGIN_EXT */)");
    wtu.glErrorShouldBe(gl, gl.INVALID_ENUM, "parameter unknown without enabling the extension");
    wtu.glErrorShouldBe(gl, gl.NO_ERROR, "should be no errors");
    shouldBeNull("gl.getParameter(0x935D /* CLIP_DEPTH_MODE_EXT */)");
    wtu.glErrorShouldBe(gl, gl.INVALID_ENUM, "parameter unknown without enabling the extension");
    wtu.glErrorShouldBe(gl, gl.NO_ERROR, "should be no errors");
}

function checkEnums() {
    debug("");
    debug("Check enums");
    shouldBe("ext.LOWER_LEFT_EXT", "0x8CA1");
    shouldBe("ext.UPPER_LEFT_EXT", "0x8CA2");

    shouldBe("ext.NEGATIVE_ONE_TO_ONE_EXT", "0x935E");
    shouldBe("ext.ZERO_TO_ONE_EXT",         "0x935F");

    shouldBe("ext.CLIP_ORIGIN_EXT",     "0x935C");
    shouldBe("ext.CLIP_DEPTH_MODE_EXT", "0x935D");
}

function checkQueries() {
    debug("");
    debug("Check default state");
    shouldBe('gl.getParameter(ext.CLIP_ORIGIN_EXT)', 'ext.LOWER_LEFT_EXT');
    shouldBe('gl.getParameter(ext.CLIP_DEPTH_MODE_EXT)', 'ext.NEGATIVE_ONE_TO_ONE_EXT');
    debug("");
    debug("Check state updates using the new function");
    ext.clipControlEXT(ext.UPPER_LEFT_EXT, ext.ZERO_TO_ONE_EXT);
    shouldBe('gl.getParameter(ext.CLIP_ORIGIN_EXT)', 'ext.UPPER_LEFT_EXT');
    shouldBe('gl.getParameter(ext.CLIP_DEPTH_MODE_EXT)', 'ext.ZERO_TO_ONE_EXT');
    ext.clipControlEXT(ext.LOWER_LEFT_EXT, ext.ZERO_TO_ONE_EXT);
    shouldBe('gl.getParameter(ext.CLIP_ORIGIN_EXT)', 'ext.LOWER_LEFT_EXT');
    shouldBe('gl.getParameter(ext.CLIP_DEPTH_MODE_EXT)', 'ext.ZERO_TO_ONE_EXT');
    ext.clipControlEXT(ext.UPPER_LEFT_EXT, ext.NEGATIVE_ONE_TO_ONE_EXT);
    shouldBe('gl.getParameter(ext.CLIP_ORIGIN_EXT)', 'ext.UPPER_LEFT_EXT');
    shouldBe('gl.getParameter(ext.CLIP_DEPTH_MODE_EXT)', 'ext.NEGATIVE_ONE_TO_ONE_EXT');
    ext.clipControlEXT(ext.LOWER_LEFT_EXT, ext.NEGATIVE_ONE_TO_ONE_EXT);
    shouldBe('gl.getParameter(ext.CLIP_ORIGIN_EXT)', 'ext.LOWER_LEFT_EXT');
    shouldBe('gl.getParameter(ext.CLIP_DEPTH_MODE_EXT)', 'ext.NEGATIVE_ONE_TO_ONE_EXT');
    wtu.glErrorShouldBe(gl, gl.NO_ERROR, "should be no errors");
}

function checkDepthMode() {
    debug("");
    debug("Check depth mode toggling");

    gl.enable(gl.DEPTH_TEST);
    gl.clear(gl.DEPTH_BUFFER_BIT);

    const program = wtu.setupProgram(gl, [wtu.simpleVertexShader,
                                          wtu.simpleColorFragmentShader]);
    gl.useProgram(program);
    const colorLoc = gl.getUniformLocation(program, "u_color");
    wtu.setupUnitQuad(gl);

    // Draw red at 0 with the default depth mode
    gl.uniform4f(colorLoc, 1, 0, 0, 1);
    ext.clipControlEXT(ext.LOWER_LEFT_EXT, ext.NEGATIVE_ONE_TO_ONE_EXT);
    wtu.drawUnitQuad(gl);
    wtu.checkCanvasRect(gl, 0, 0, w, h, [255, 0, 0, 255]);

    // Draw green at 0, depth test must fail
    gl.uniform4f(colorLoc, 0, 1, 0, 1);
    wtu.drawUnitQuad(gl);
    wtu.checkCanvasRect(gl, 0, 0, w, h, [255, 0, 0, 255]);

    // Draw green at 0 after switching the depth mode
    ext.clipControlEXT(ext.LOWER_LEFT_EXT, ext.ZERO_TO_ONE_EXT);
    wtu.drawUnitQuad(gl);
    wtu.checkCanvasRect(gl, 0, 0, w, h, [0, 255, 0, 255]);

    wtu.glErrorShouldBe(gl, gl.NO_ERROR, "should be no errors");
}

function checkClipOrigin() {
    debug("");
    debug("Check clip origin toggling");

    gl.disable(gl.DEPTH_TEST);

    const vertexShader = `
        attribute vec4 vPosition;
        varying float y;
        void main() {
            gl_Position = vPosition;
            y = vPosition.y;
        }`;
    const fragmentShader = `
        precision mediump float;
        varying float y;
        void main() {
            if (y > 0.0) {
                gl_FragColor = vec4(1.0, 0.0, 0.0, 1.0);
            } else {
                gl_FragColor = vec4(0.0, 1.0, 0.0, 1.0);
            }
        }`;

    const program = wtu.setupProgram(gl, [vertexShader, fragmentShader]);
    gl.useProgram(program);

    wtu.setupUnitQuad(gl);

    ext.clipControlEXT(ext.LOWER_LEFT_EXT, ext.NEGATIVE_ONE_TO_ONE_EXT);
    wtu.drawUnitQuad(gl);
    wtu.checkCanvasRect(gl, 0, 0, w, h / 2 - 2, [0, 255, 0, 255]);
    wtu.checkCanvasRect(gl, 0, h / 2 + 2, w, h / 2 - 2, [255, 0, 0, 255]);

    ext.clipControlEXT(ext.UPPER_LEFT_EXT, ext.NEGATIVE_ONE_TO_ONE_EXT);
    wtu.drawUnitQuad(gl);
    wtu.checkCanvasRect(gl, 0, 0, w, h / 2 - 2, [255, 0, 0, 255]);
    wtu.checkCanvasRect(gl, 0, h / 2 + 2, w, h / 2 - 2, [0, 255, 0, 255]);

    wtu.glErrorShouldBe(gl, gl.NO_ERROR, "should be no errors");
}

function runTestExtension() {
    checkEnums();
    checkQueries();
    checkDepthMode();
    checkClipOrigin();
}

function runTest() {
    if (!gl) {
        testFailed("WebGL context does not exist");
        return;
    }
    testPassed("WebGL context exists");

    runTestNoExtension();

    ext = gl.getExtension("EXT_clip_control");

    wtu.runExtensionSupportedTest(gl, "EXT_clip_control", ext !== null);

    if (ext !== null) {
        runTestExtension();
    } else {
        testPassed("No EXT_clip_control support -- this is legal");
    }
}

runTest();

var successfullyParsed = true;
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